;;; repeat.el --- convenient way to repeat the previous command;; Copyright (C) 1998 Free Software Foundation, Inc.;; Author: Will Mengarini <seldon@eskimo.com>;; Created: Mo 02 Mar 98;; Version: 0.51, We 13 May 98;; Keywords: convenience, vi, repeat;; This file is part of GNU Emacs.;; This program is free software; you can redistribute it and/or modify;; it under the terms of the GNU General Public License as published by;; the Free Software Foundation; either version 2, or (at your option);; any later version.;; This program is distributed in the hope that it will be useful,;; but WITHOUT ANY WARRANTY; without even the implied warranty of;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the;; GNU General Public License for more details.;; You should have received a copy of the GNU General Public License;; along with GNU Emacs; see the file COPYING. If not, write to the;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,;; Boston, MA 02111-1307, USA.;;; Commentary:;; Sometimes the fastest way to get something done is just to lean on a key;;; moving forward through a series of words by leaning on M-f is an example.;; But 'forward-page is orthodoxily bound to C-x ], so moving forward through;; several pages requires;; Loop until desired page is reached:;; Hold down control key with left pinkie.;; Tap <x>.;; Lift left pinkie off control key.;; Tap <]>.;; This is a pain in the ass.;; This package defines a command that repeats the preceding command,;; whatever that was, including its arguments, whatever they were.;; This command is connected to the key C-x z.;; To repeat the previous command once, type C-x z.;; To repeat it a second time immediately after, type just z.;; By typing z again and again, you can repeat the command over and over.;; This works correctly inside a keyboard macro as far as recording and;; playback go, but `edit-kbd-macro' gets it wrong. That shouldn't really;; matter; if you need to edit something like;; C-x ] ;; forward-page;; C-x z ;; repeat;; zz ;; self-insert-command * 2;; C-x ;; Control-X-prefix;; you can just kill the bogus final 2 lines, then duplicate the repeat line;; as many times as it's really needed. Also, `edit-kbd-macro' works;; correctly if `repeat' is invoked through a rebinding to a single keystroke;; and the global variable repeat-on-final-keystroke is set to a value;; that doesn't include that keystroke. For example, the lines;; (global-set-key "\C-z" 'repeat);; (setq repeat-on-final-keystroke "z");; in your .emacs would allow `edit-kbd-macro' to work correctly when C-z was;; used in a keyboard macro to invoke `repeat', but would still allow C-x z;; to be used for `repeat' elsewhere. The real reason for documenting this;; isn't that anybody would need it for the `edit-kbd-macro' problem, but;; that there might be other unexpected ramifications of re-executing on;; repetitions of the final keystroke, and this shows how to do workarounds.;; If the preceding command had a prefix argument, that argument is applied;; to the repeat command, unless the repeat command is given a new prefix;; argument, in which case it applies that new prefix argument to the;; preceding command. This means a key sequence like C-u - C-x C-t can be;; repeated. (It shoves the preceding line upward in the buffer.);; Here are some other key sequences with which repeat might be useful:;; C-u - C-t [shove preceding character backward in line];; C-u - M-t [shove preceding word backward in sentence];; C-x ^ enlarge-window [one line] (assuming frame has > 1 window);; C-u - C-x ^ [shrink window one line];; C-x ` next-error;; C-u - C-x ` [previous error];; C-x DEL backward-kill-sentence;; C-x e call-last-kbd-macro;; C-x r i insert-register;; C-x r t string-rectangle;; C-x TAB indent-rigidly [one character];; C-u - C-x TAB [outdent rigidly one character];; C-x { shrink-window-horizontally;; C-x } enlarge-window-horizontally;; This command was first called `vi-dot', because;; it was inspired by the `.' command in the vi editor,;; but it was renamed to make its name more meaningful.;;; Code:(eval-when-compile(require'cl));;;;; ************************* USER OPTIONS ************************** ;;;;;(defcustomrepeat-too-dangerous'(kill-this-buffer)"Commands too dangerous to repeat with \\[repeat].":group'convenience:type'(repeatfunction));; If the last command was self-insert-command, the char to be inserted was;; obtained by that command from last-command-char, which has now been;; clobbered by the command sequence that invoked `repeat'. We could get it;; from (recent-keys) & set last-command-char to that, "unclobbering" it, but;; this has the disadvantage that if the user types a sequence of different;; chars then invokes repeat, only the final char will be inserted. In vi,;; the dot command can reinsert the entire most-recently-inserted sequence.(defvarrepeat-message-functionnil"If non-nil, function used by `repeat' command to say what it's doing.Message is something like \"Repeating command glorp\".To disable such messages, set this variable to `ignore'. To customizedisplay, assign a function that takes one string as an arg and displaysit however you want.")(defcustomrepeat-on-final-keystroket"Allow `repeat' to re-execute for repeating lastchar of a key sequence.If this variable is t, `repeat' determines what key sequenceit was invoked by, extracts the final character of that sequence, andre-executes as many times as that final character is hit; so for exampleif `repeat' is bound to C-x z, typing C-x z z z repeats the previous command3 times. If this variable is a sequence of characters, then re-executiononly occurs if the final character by which `repeat' was invoked is amember of that sequence. If this variable is nil, no re-execution occurs.":group'convenience:type'boolean);;;;; ****************** HACKS TO THE REST OF EMACS ******************* ;;;;;;; The basic strategy is to use last-command, a variable built in to Emacs.;; There are 2 issues that complicate this strategy. The first is that;; last-command is given a bogus value when any kill command is executed;;; this is done to make it easy for `yank-pop' to know that it's being invoked;; after a kill command. The second is that the meaning of the command is;; often altered by the prefix arg, but although Emacs (19.34) has a;; builtin prefix-arg specifying the arg for the next command, as well as a;; builtin current-prefix-arg, it has no builtin last-prefix-arg.;; There's a builtin (this-command-keys), the return value of which could be;; executed with (command-execute), but there's no (last-command-keys).;; Using (last-command-keys) if it existed wouldn't be optimal, however,;; since it would complicate checking membership in repeat-too-dangerous.;; It would of course be trivial to implement last-prefix-arg &;; true-last-command by putting something in post-command-hook, but that;; entails a performance hit; the approach taken below avoids that.;; First cope with (kill-region). It's straightforward to advise it to save;; the true value of this-command before clobbering it.(require'advice)(defvarrepeat-last-kill-commandnil"True value of `this-command' before (`kill-region') clobbered it.");; Coping with strings of self-insert commands gets hairy when they interact;; with auto-filling. Most problems are eliminated by remembering what we're;; self-inserting, so we only need to get it from the undo information once.(defvarrepeat-last-self-insertnil"If last repeated command was `self-insert-command', it inserted this.");; That'll require another keystroke count so we know we're in a string of;; repetitions of self-insert commands:(defvarrepeat-num-input-keys-at-self-insert-1"# key sequences read in Emacs session when `self-insert-command' repeated.");;;;; *************** ANALOGOUS HACKS TO `repeat' ITSELF **************** ;;;;;;; That mechanism of checking num-input-keys to figure out what's really;; going on can be useful to other commands that need to fine-tune their;; interaction with repeat. Instead of requiring them to advise repeat, we;; can just defvar the value they need here, & setq it in the repeat command:(defvarrepeat-num-input-keys-at-repeat-1"# key sequences read in Emacs session when `repeat' last invoked.");; Also, we can assign a name to the test for which that variable is;; intended, which thereby documents here how to use it, & makes code that;; uses it self-documenting:(defsubstrepeat-is-really-this-command()"Return t if this command is happening because user invoked `repeat'.Usually, when a command is executing, the Emacs builtin variable`this-command' identifies the command the user invoked. Some commands modifythat variable on the theory they're doing more good than harm; `repeat' doesthat, and usually does do more good than harm. However, like all do-gooders,sometimes `repeat' gets surprising results from its altruism. The value ofthis function is always whether the value of `this-command' would've been'repeat if `repeat' hadn't modified it."(=repeat-num-input-keys-at-repeatnum-input-keys));; An example of the use of (repeat-is-really-this-command) may still be;; available in <http://www.eskimo.com/~seldon/dotemacs.el>; search for;; "defun wm-switch-buffer".;;;;; ******************* THE REPEAT COMMAND ITSELF ******************* ;;;;;;;;###autoload(defunrepeat(repeat-arg)"Repeat most recently executed command.With prefix arg, apply new prefix arg to that command; otherwise, maintainprefix arg of most recently executed command if it had one.This command is named after the `.' command in the vi editor.If this command is invoked by a multi-character key sequence, it can thenbe repeated by repeating the final character of that sequence. This behaviorcan be modified by the global variable `repeat-on-final-keystroke'.";; The most recently executed command could be anything, so surprises could;; result if it were re-executed in a context where new dynamically;; localized variables were shadowing global variables in a `let' clause in;; here. (Remember that GNU Emacs 19 is dynamically localized.);; To avoid that, I tried the `lexical-let' of the Common Lisp extensions,;; but that entails a very noticeable performance hit, so instead I use the;; "repeat-" prefix, reserved by this package, for *local* variables that;; might be visible to re-executed commands, including this function's arg.(interactive"P")(setqthis-commandreal-last-commandrepeat-num-input-keys-at-repeatnum-input-keys)(when(eqreal-last-command'mode-exit)(error"real-last-command is mode-exit & can't be repeated"))(when(memqreal-last-commandrepeat-too-dangerous)(error"Command %S too dangerous to repeat automatically"real-last-command))(when(nullrepeat-arg)(setqrepeat-arglast-prefix-arg));; Now determine whether to loop on repeated taps of the final character;; of the key sequence that invoked repeat. The Emacs global;; last-command-char contains the final character now, but may not still;; contain it after the previous command is repeated, so the character;; needs to be saved.(let((repeat-repeat-char(if(eqrepeat-on-final-keystroket);; allow any final input event that was a character(when(eqlast-command-charlast-command-event)last-command-char);; allow only specified final keystrokes(car(memqlast-command-char(listify-key-sequencerepeat-on-final-keystroke))))))(if(memqreal-last-command'(exit-minibufferminibuffer-complete-and-exitself-insert-and-exit))(let((repeat-command(carcommand-history)))(repeat-message"Repeating %S"repeat-command)(evalrepeat-command))(if(nullrepeat-arg)(repeat-message"Repeating command %S"real-last-command)(setqcurrent-prefix-argrepeat-arg)(repeat-message"Repeating command %S %S"repeat-argreal-last-command))(if(eqreal-last-command'self-insert-command)(let((insertion(if(<=(-num-input-keysrepeat-num-input-keys-at-self-insert)1)repeat-last-self-insert(let((range(nth1buffer-undo-list)))(condition-casenil(setqrepeat-last-self-insert(buffer-substring(carrange)(cdrrange)))(error(error"%s %s %s";Danger, Will Robinson! "repeat can't intuit what you""inserted before auto-fill""clobbered it, sorry")))))))(setqrepeat-num-input-keys-at-self-insertnum-input-keys)(looprepeat(prefix-numeric-valuerepeat-arg)do(repeat-self-insertinsertion)))(call-interactivelyreal-last-command)))(whenrepeat-repeat-char;; A simple recursion here gets into trouble with max-lisp-eval-depth;; on long sequences of repetitions of a command like `forward-word';; (only 32 repetitions are possible given the default value of 200 for;; max-lisp-eval-depth), but if I now locally disable the repeat char I;; can iterate indefinitely here around a single level of recursion.(let(repeat-on-final-keystroke)(while(eq(read-event)repeat-repeat-char)(repeatrepeat-arg))(setqunread-command-events(listlast-input-event))))))(defunrepeat-self-insert(string)(let((i0))(while(<i(lengthstring))(let((last-command-char(arefstringi)))(self-insert-command1))(setqi(1+i)))))(defunrepeat-message(format&restargs)"Like `message' but displays with `repeat-message-function' if non-nil."(let((message(apply'formatformatargs)))(ifrepeat-message-function(funcallrepeat-message-functionmessage)(message"%s"message))));; OK, there's one situation left where that doesn't work correctly: when the;; most recent self-insertion provoked an auto-fill. The problem is that;; unravelling the undo information after an auto-fill is too hard, since all;; kinds of stuff can get in there as a result of comment prefixes etc. It'd;; be possible to advise do-auto-fill to record the most recent;; self-insertion before it does its thing, but that's a performance hit on;; auto-fill, which already has performance problems; so it's better to just;; leave it like this. If text didn't provoke an auto-fill when the user;; typed it, this'll correctly repeat its self-insertion, even if the;; repetition does cause auto-fill.;; If you wanted perfection, probably it'd be necessary to hack do-auto-fill;; into 2 functions, maybe-do-auto-fill & really-do-auto-fill, because only;; really-do-auto-fill should be advised. As things are, either the undo;; information would need to be scanned on every do-auto-fill invocation, or;; the code at the top of do-auto-fill deciding whether filling is necessary;; would need to be duplicated in the advice, wasting execution time when;; filling does turn out to be necessary.;; I thought maybe this story had a moral, something about functional;; decomposition; but now I'm not even sure of that, since a function;; call per se is a performance hit, & even the code that would;; correspond to really-do-auto-fill has performance problems that;; can make it necessary to stop typing while Emacs catches up.;; Maybe the real moral is that perfection is a chimera.;; Ah, hell, it's all going to fall into a black hole someday anyway.;;;;; ************************* EMACS CONTROL ************************* ;;;;;(provide'repeat);;; repeat.el ends here